81143400 has 192 divisors, whose sum is σ = 276232320. Its totient is φ = 19584000.

The previous prime is 81143393. The next prime is 81143407. The reversal of 81143400 is 434118.

It is an interprime number because it is at equal distance from previous prime (81143393) and next prime (81143407).

It is not an unprimeable number, because it can be changed into a prime (81143407) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 787749 + ... + 787851.

It is an arithmetic number, because the mean of its divisors is an integer number (1438710).

Almost surely, 2^81143400 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81143400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138116160).

81143400 is an abundant number, since it is smaller than the sum of its proper divisors (195088920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81143400 is a wasteful number, since it uses less digits than its factorization.

81143400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 236 (or 227 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 81143400 is about 9007.9631437967. The cubic root of 81143400 is about 432.9300521537.

Adding to 81143400 its reverse (434118), we get a palindrome (81577518).

The spelling of 81143400 in words is "eighty-one million, one hundred forty-three thousand, four hundred".